Messages in this thread | | | Date | Mon, 10 Feb 2003 03:48:08 -0800 | From | Andrew Morton <> | Subject | Re: stochastic fair queueing in the elevator [Re: [BENCHMARK] 2.4.20-ck3 / aa / rmap with contest] |
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Andrea Arcangeli <andrea@suse.de> wrote: > > It's the readahead in my tree that allows the reads to use the max scsi > command size. It has nothing to do with the max scsi command size > itself.
Oh bah.
- *max_ra++ = vm_max_readahead; + *max_ra = ((128*4) >> (PAGE_SHIFT - 10)) - 1;
Well of course that will get bigger bonnie numbers, for exactly the reasons I've explained. It will seek between files after every 512k rather than after every 128k.
> You can wait 10 minutes and still such command can't grow. This is why > claiming anticipatory scheduling can decrease the need for readahead > doesn't make much sense to me, there are important things you just can't > achieve by only waiting. >
The anticipatory scheduler can easily permit 512k of reading before seeking away to another file. In fact it can allow much more, without requiring that readhead be cranked up.
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